An interior body is housed in a tubular exterior body. The interior body includes a spring portion, a movable portion, and a fixing portion, which are integrated together. Elastic arms are disposed on the movable portion so as to extend downward. Each elastic arm includes, at a lower end portion, an elastically pressing portion, which is elastically pressed against a tubular internal surface of the exterior body. Since the elastically pressing portion is elastically pressed against the exterior body, electric signals are more likely to flow between the movable portion and the exterior body and more likely to be prevented from leaking to the spring portion.